Worldwatch Institute & Brown, L. R. (1999). State of the world 1999: A Worldwatch Institute report on progress toward a sustainable society. W. W. Norton & Company.
Lua i Stíl Chicago (17ú heag.)Worldwatch Institute agus Lester Russell Brown. State of the World 1999: A Worldwatch Institute Report on Progress Toward a Sustainable Society. New York ; London: W. W. Norton & Company, 1999.
Lua MLA (8ú heag.)Worldwatch Institute agus Lester Russell Brown. State of the World 1999: A Worldwatch Institute Report on Progress Toward a Sustainable Society. W. W. Norton & Company, 1999.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.